`The Comeback' tells the story of a B-list sitcom star so desperate to revive her career that she agrees to star in a reality television show called, appropriately enough, `The Comeback'. Cameras follow Valerie Cherish's every move as she angles to keep her head above the Hollywood fray, even as she's woefully out of touch with modern show business. And in the madness that is network television, there is nothing braver than a 40-year-old ingenue who's not quite ready to give up the spotlight.